Convex mirrors are well-known as devices which are useful for providing a viewer with an expanded field of view by virtue of the reflections which are visible in the mirror. By virtue of their optical properties, convex mirrors provide a substantially wider, albeit distorted, field of view than that which is available from a conventional flat mirror. Further, by virtue of their usefulness as security and anti-theft devices, convex mirrors have become commonplace fixtures in commercial establishments, for example, retail stores. Such a device is shown by Ross in U.S. Pat. No. 3,316,052.
Mirrors have long been used as attractive backgrounds for signs. It has long been known to superimpose an advertising message on a mirrored background as a method of attracting a viewer's attention to the message. However, these signs have typically been used as decorative and advertising devices only, inasmuch as the conventional mirror provides limited enhancement to the product point of sale, for example, on the wall of a tavern or similar establishment, for the purpose of directing a purchaser's attention to a particular product brand name. See, for example, U.S. Pat. No. 1,849,708, issued to Colbert, et al.
The application of a desired advertising message, pattern, or art on a convex acrylic mirror presents significant production problems. The mirrored surface of such devices is the result of deposition of vaporized metals on one surface of a two-sided acrylic material. This process takes place, typically, in a high-temperature vacuum environment.
Traditionally, application of such messages, advertising, or art has been attempted by selective mechanical removal of portions of the deposited film. See Japanese Patent 166,744 issued to S. Hoo, and German Patent 28, 33, 133, issued to Klaus Kall.
Conventional masking techniques are often unacceptable in the industrial environment. Adhesive backed-tapes and spray-on latex masks tend to emit a variety of gases when heated. These gases combine with the vaporized metals during the deposition process, creating opaque chemical compounds (for example, aluminum oxide) which contaminate the acrylic surface, leaving visible and undesirable blemishes, particularly where a transparent area is desired on the finished surface.
A much simplified and improved method for the manufacture of such mirrors is disclosed herein. Utilizing this method, a novel device is created which provides crisp definition of the message or art, insuring improved transparency of the non-mirrored areas of the surface of the acrylic.
It is a further object of the invention, therefore, to create a combined advertising and security medium which is aesthetically pleasing, commercially useful and economically beneficial by combining a surveillance and advertising device into a single component.